Health

Ascorbate stabilizes the differentiated state and reduces the ability of Rous sarcoma virus to replicate and to uniformly transform cell cultures

Article Abstract:

The Rous sarcoma virus (RSV) was first discovered in and isolated from chickens. When RSV is added to chick embryo cells grown in culture, the virus causes the cells to grow at a rapid rate and to be transformed into cancer cells. However, RSV infection in chickens rarely causes malignant connective tissue tumors (sarcomas). The exact reason for this is not clear, but it has been suggested that the conditions used to culture the embryologic cell may increase the ability of RSV to promote the cell transformation. Previous studies have reported that removing ascorbate (vitamin C) from the cell culture increases the ability of RSV to transform the cells into cancer cells. To further investigate the role of ascorbate in the growth of cancer cells, normal connective tissue cells from chick embryos were grown in culture in the presence and absence of ascorbate and RSV. Addition or removal of ascorbate from the cell cultures had no effect on normal chick embryo cells. With the addition of RSV to the cultures, they were transformed into cancer cells. When these cells were grown in the absence of ascorbate, the ability of RSV to transform them into cancer cells was increased. When ascorbate was added to the RSV cultures, the ability of the virus to replicate and transform the cells into cancer cells was decreased. These results demonstrate that ascorbate impairs the ability of RSV to transform chick embryo connective tissue cells into cancer cells by reducing virus replication and increasing the production of proteins that favor the differentiated (noncancerous) state. (Consumer Summary produced by Reliance Medical Information, Inc.)

Cesarean deliveries and maternal-infant HIV transmission: results from a prospective study in South Africa

Article Abstract:

Cesarean section may reduce the risk that a pregnant woman will transmit HIV to her baby at birth. Researchers followed 141 newborn infants of 136 mothers in Durban, South Africa, to determine the effect mode of delivery has on HIV transmission during childbirth. Eighty-eight women delivered vaginally and 48 had a cesarean. Women who had a cesarean were only half as likely to transmit the virus to their baby. Cesarean performed because of premature rupture of membranes was not associated with an increased risk of HIV transmission. In fact, cesareans performed in the absence of serious obstetric complications were associated with one-fifth the risk of HIV transmission. In women delivering vaginally, prolonged labor and premature rupture of membranes did not increase the risk of HIV transmission. Survival rates were similar in infants delivered vaginally or by cesarean. Many developing countries will be unable to perform cesareans safely and inexpensively.